Aniline and certain alkyl derivatives thereof are known antiknock agents. However, aniline derivatives which are also tertiary amines--i.e., those containing no N--H bonds--are poor antiknock agents. U.S. Pat. Nos. 3,523,769 and 3,706,541 whose disclosures are incorporated herein by reference deal with the use of aniline and aniline-based diamines as antiknock agents.